Antibiotic Resistance: New Superbug Resistant To A Once-Powerful Drug Emerges In China

Last December, a British government-commissioned review found that growing resistance to drugs, including antibiotics, in microbes and the rise of superbugs could cast medicine back to the dark ages and lead to the deaths of over 10 million people a year by 2050. Now, as the world marks its first antibiotic awareness week, further evidence of this antibiotic apocalypse has emerged from a study conducted in China.

According to the study, published Wednesday in the journal Lancet, a new gene that makes bacteria resistant to a class of last-resort antibiotics has been discovered in humans and livestock in China. Moreover, evidence is now emerging that it might have spread to the neighboring nations of Laos and Malaysia.

The gene -- named mcr-1 -- was found on plasmids, which are mobile DNA strands that can be easily copied between different bacteria, suggesting an “alarming potential” for it to spread across diverse bacterial populations. This gene, the researchers said, is widespread in bacteria known as Enterobacteriaceae -- a large family that includes Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella -- and provides resistance to a class of antibiotics known as polymyxins, which includes colistin that is used as a drug of last resort.

Colistin is also widely used in livestock farming, with China currently being one of the world's largest users and producers of the drug for agriculture and veterinary use.

During the study, the gene was found in 20 percent of pigs tested, 15 percent of the raw meat samples analyzed and 16 of 1,322 hospitalized human patients.

“These are extremely worrying results,” Jian-Hua Liu from South China Agricultural University in Guangzhou, author of the report, said in a statement. “The polymyxins were the last class of antibiotics in which resistance was incapable of spreading from cell to cell. … Our results reveal the emergence of the first polymyxin resistance gene that is readily passed between common bacteria such as Escherichia coli and Klesbsiella pneumoniae, suggesting that the progression from extensive drug resistance to pandrug resistance is inevitable.”

In order to prevent the creation of a bacteria resistant to all treatment -- a so-called nightmare bacteria -- many have now called for a ban on using the same drug in veterinary and human medicine.

“The links between agricultural use of colistin, colistin resistance in slaughtered animals, colistin resistance in food, and colistin resistance in human beings are now complete. One of the few solutions to uncoupling these connections is limitation or cessation of colistin use in agriculture,” David Paterson and Patrick Harris from the University of Queensland, Brisbane, Australia, who weren’t involved in the study, wrote, in a commentary in the Lancet. “Failure to do so will create a public health problem of major dimensions.”